diff --git a/GPBMetadata/Opentelemetry/Proto/Logs/V1/Logs.php b/GPBMetadata/Opentelemetry/Proto/Logs/V1/Logs.php
index e3ce8d4..9af0fcc 100644
Binary files a/GPBMetadata/Opentelemetry/Proto/Logs/V1/Logs.php and b/GPBMetadata/Opentelemetry/Proto/Logs/V1/Logs.php differ
diff --git a/GPBMetadata/Opentelemetry/Proto/Metrics/V1/Metrics.php b/GPBMetadata/Opentelemetry/Proto/Metrics/V1/Metrics.php
index 3da1638..cbb0950 100644
Binary files a/GPBMetadata/Opentelemetry/Proto/Metrics/V1/Metrics.php and b/GPBMetadata/Opentelemetry/Proto/Metrics/V1/Metrics.php differ
diff --git a/Opentelemetry/Proto/Common/V1/InstrumentationScope.php b/Opentelemetry/Proto/Common/V1/InstrumentationScope.php
index aa84bbe..d2b4b6f 100644
--- a/Opentelemetry/Proto/Common/V1/InstrumentationScope.php
+++ b/Opentelemetry/Proto/Common/V1/InstrumentationScope.php
@@ -27,6 +27,10 @@ class InstrumentationScope extends \Google\Protobuf\Internal\Message
      */
     protected $version = '';
     /**
+     * Additional attributes that describe the scope. [Optional].
+     * Attribute keys MUST be unique (it is not allowed to have more than one
+     * attribute with the same key).
+     *
      * Generated from protobuf field <code>repeated .opentelemetry.proto.common.v1.KeyValue attributes = 3;</code>
      */
     private $attributes;
@@ -45,6 +49,9 @@ class InstrumentationScope extends \Google\Protobuf\Internal\Message
      *           An empty instrumentation scope name means the name is unknown.
      *     @type string $version
      *     @type \Opentelemetry\Proto\Common\V1\KeyValue[]|\Google\Protobuf\Internal\RepeatedField $attributes
+     *           Additional attributes that describe the scope. [Optional].
+     *           Attribute keys MUST be unique (it is not allowed to have more than one
+     *           attribute with the same key).
      *     @type int $dropped_attributes_count
      * }
      */
@@ -102,6 +109,10 @@ public function setVersion($var)
     }
 
     /**
+     * Additional attributes that describe the scope. [Optional].
+     * Attribute keys MUST be unique (it is not allowed to have more than one
+     * attribute with the same key).
+     *
      * Generated from protobuf field <code>repeated .opentelemetry.proto.common.v1.KeyValue attributes = 3;</code>
      * @return \Google\Protobuf\Internal\RepeatedField
      */
@@ -111,6 +122,10 @@ public function getAttributes()
     }
 
     /**
+     * Additional attributes that describe the scope. [Optional].
+     * Attribute keys MUST be unique (it is not allowed to have more than one
+     * attribute with the same key).
+     *
      * Generated from protobuf field <code>repeated .opentelemetry.proto.common.v1.KeyValue attributes = 3;</code>
      * @param \Opentelemetry\Proto\Common\V1\KeyValue[]|\Google\Protobuf\Internal\RepeatedField $var
      * @return $this
diff --git a/Opentelemetry/Proto/Logs/V1/LogRecord.php b/Opentelemetry/Proto/Logs/V1/LogRecord.php
index e05c106..caca11f 100644
--- a/Opentelemetry/Proto/Logs/V1/LogRecord.php
+++ b/Opentelemetry/Proto/Logs/V1/LogRecord.php
@@ -81,25 +81,36 @@ class LogRecord extends \Google\Protobuf\Internal\Message
      * defined in W3C Trace Context specification. 24 most significant bits are reserved
      * and must be set to 0. Readers must not assume that 24 most significant bits
      * will be zero and must correctly mask the bits when reading 8-bit trace flag (use
-     * flags & TRACE_FLAGS_MASK). [Optional].
+     * flags & LOG_RECORD_FLAGS_TRACE_FLAGS_MASK). [Optional].
      *
      * Generated from protobuf field <code>fixed32 flags = 8;</code>
      */
     protected $flags = 0;
     /**
      * A unique identifier for a trace. All logs from the same trace share
-     * the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes
-     * is considered invalid. Can be set for logs that are part of request processing
-     * and have an assigned trace id. [Optional].
+     * the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes OR
+     * of length other than 16 bytes is considered invalid (empty string in OTLP/JSON
+     * is zero-length and thus is also invalid).
+     * This field is optional.
+     * The receivers SHOULD assume that the log record is not associated with a
+     * trace if any of the following is true:
+     *   - the field is not present,
+     *   - the field contains an invalid value.
      *
      * Generated from protobuf field <code>bytes trace_id = 9;</code>
      */
     protected $trace_id = '';
     /**
      * A unique identifier for a span within a trace, assigned when the span
-     * is created. The ID is an 8-byte array. An ID with all zeroes is considered
-     * invalid. Can be set for logs that are part of a particular processing span.
-     * If span_id is present trace_id SHOULD be also present. [Optional].
+     * is created. The ID is an 8-byte array. An ID with all zeroes OR of length
+     * other than 8 bytes is considered invalid (empty string in OTLP/JSON
+     * is zero-length and thus is also invalid).
+     * This field is optional. If the sender specifies a valid span_id then it SHOULD also
+     * specify a valid trace_id.
+     * The receivers SHOULD assume that the log record is not associated with a
+     * span if any of the following is true:
+     *   - the field is not present,
+     *   - the field contains an invalid value.
      *
      * Generated from protobuf field <code>bytes span_id = 10;</code>
      */
@@ -149,17 +160,28 @@ class LogRecord extends \Google\Protobuf\Internal\Message
      *           defined in W3C Trace Context specification. 24 most significant bits are reserved
      *           and must be set to 0. Readers must not assume that 24 most significant bits
      *           will be zero and must correctly mask the bits when reading 8-bit trace flag (use
-     *           flags & TRACE_FLAGS_MASK). [Optional].
+     *           flags & LOG_RECORD_FLAGS_TRACE_FLAGS_MASK). [Optional].
      *     @type string $trace_id
      *           A unique identifier for a trace. All logs from the same trace share
-     *           the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes
-     *           is considered invalid. Can be set for logs that are part of request processing
-     *           and have an assigned trace id. [Optional].
+     *           the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes OR
+     *           of length other than 16 bytes is considered invalid (empty string in OTLP/JSON
+     *           is zero-length and thus is also invalid).
+     *           This field is optional.
+     *           The receivers SHOULD assume that the log record is not associated with a
+     *           trace if any of the following is true:
+     *             - the field is not present,
+     *             - the field contains an invalid value.
      *     @type string $span_id
      *           A unique identifier for a span within a trace, assigned when the span
-     *           is created. The ID is an 8-byte array. An ID with all zeroes is considered
-     *           invalid. Can be set for logs that are part of a particular processing span.
-     *           If span_id is present trace_id SHOULD be also present. [Optional].
+     *           is created. The ID is an 8-byte array. An ID with all zeroes OR of length
+     *           other than 8 bytes is considered invalid (empty string in OTLP/JSON
+     *           is zero-length and thus is also invalid).
+     *           This field is optional. If the sender specifies a valid span_id then it SHOULD also
+     *           specify a valid trace_id.
+     *           The receivers SHOULD assume that the log record is not associated with a
+     *           span if any of the following is true:
+     *             - the field is not present,
+     *             - the field contains an invalid value.
      * }
      */
     public function __construct($data = NULL) {
@@ -400,7 +422,7 @@ public function setDroppedAttributesCount($var)
      * defined in W3C Trace Context specification. 24 most significant bits are reserved
      * and must be set to 0. Readers must not assume that 24 most significant bits
      * will be zero and must correctly mask the bits when reading 8-bit trace flag (use
-     * flags & TRACE_FLAGS_MASK). [Optional].
+     * flags & LOG_RECORD_FLAGS_TRACE_FLAGS_MASK). [Optional].
      *
      * Generated from protobuf field <code>fixed32 flags = 8;</code>
      * @return int
@@ -415,7 +437,7 @@ public function getFlags()
      * defined in W3C Trace Context specification. 24 most significant bits are reserved
      * and must be set to 0. Readers must not assume that 24 most significant bits
      * will be zero and must correctly mask the bits when reading 8-bit trace flag (use
-     * flags & TRACE_FLAGS_MASK). [Optional].
+     * flags & LOG_RECORD_FLAGS_TRACE_FLAGS_MASK). [Optional].
      *
      * Generated from protobuf field <code>fixed32 flags = 8;</code>
      * @param int $var
@@ -431,9 +453,14 @@ public function setFlags($var)
 
     /**
      * A unique identifier for a trace. All logs from the same trace share
-     * the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes
-     * is considered invalid. Can be set for logs that are part of request processing
-     * and have an assigned trace id. [Optional].
+     * the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes OR
+     * of length other than 16 bytes is considered invalid (empty string in OTLP/JSON
+     * is zero-length and thus is also invalid).
+     * This field is optional.
+     * The receivers SHOULD assume that the log record is not associated with a
+     * trace if any of the following is true:
+     *   - the field is not present,
+     *   - the field contains an invalid value.
      *
      * Generated from protobuf field <code>bytes trace_id = 9;</code>
      * @return string
@@ -445,9 +472,14 @@ public function getTraceId()
 
     /**
      * A unique identifier for a trace. All logs from the same trace share
-     * the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes
-     * is considered invalid. Can be set for logs that are part of request processing
-     * and have an assigned trace id. [Optional].
+     * the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes OR
+     * of length other than 16 bytes is considered invalid (empty string in OTLP/JSON
+     * is zero-length and thus is also invalid).
+     * This field is optional.
+     * The receivers SHOULD assume that the log record is not associated with a
+     * trace if any of the following is true:
+     *   - the field is not present,
+     *   - the field contains an invalid value.
      *
      * Generated from protobuf field <code>bytes trace_id = 9;</code>
      * @param string $var
@@ -463,9 +495,15 @@ public function setTraceId($var)
 
     /**
      * A unique identifier for a span within a trace, assigned when the span
-     * is created. The ID is an 8-byte array. An ID with all zeroes is considered
-     * invalid. Can be set for logs that are part of a particular processing span.
-     * If span_id is present trace_id SHOULD be also present. [Optional].
+     * is created. The ID is an 8-byte array. An ID with all zeroes OR of length
+     * other than 8 bytes is considered invalid (empty string in OTLP/JSON
+     * is zero-length and thus is also invalid).
+     * This field is optional. If the sender specifies a valid span_id then it SHOULD also
+     * specify a valid trace_id.
+     * The receivers SHOULD assume that the log record is not associated with a
+     * span if any of the following is true:
+     *   - the field is not present,
+     *   - the field contains an invalid value.
      *
      * Generated from protobuf field <code>bytes span_id = 10;</code>
      * @return string
@@ -477,9 +515,15 @@ public function getSpanId()
 
     /**
      * A unique identifier for a span within a trace, assigned when the span
-     * is created. The ID is an 8-byte array. An ID with all zeroes is considered
-     * invalid. Can be set for logs that are part of a particular processing span.
-     * If span_id is present trace_id SHOULD be also present. [Optional].
+     * is created. The ID is an 8-byte array. An ID with all zeroes OR of length
+     * other than 8 bytes is considered invalid (empty string in OTLP/JSON
+     * is zero-length and thus is also invalid).
+     * This field is optional. If the sender specifies a valid span_id then it SHOULD also
+     * specify a valid trace_id.
+     * The receivers SHOULD assume that the log record is not associated with a
+     * span if any of the following is true:
+     *   - the field is not present,
+     *   - the field contains an invalid value.
      *
      * Generated from protobuf field <code>bytes span_id = 10;</code>
      * @param string $var
diff --git a/Opentelemetry/Proto/Logs/V1/LogRecordFlags.php b/Opentelemetry/Proto/Logs/V1/LogRecordFlags.php
index 9927400..de6f388 100644
--- a/Opentelemetry/Proto/Logs/V1/LogRecordFlags.php
+++ b/Opentelemetry/Proto/Logs/V1/LogRecordFlags.php
@@ -7,24 +7,32 @@
 use UnexpectedValueException;
 
 /**
- * Masks for LogRecord.flags field.
+ * LogRecordFlags is defined as a protobuf 'uint32' type and is to be used as
+ * bit-fields. Each non-zero value defined in this enum is a bit-mask.
+ * To extract the bit-field, for example, use an expression like:
+ *   (logRecord.flags & LOG_RECORD_FLAGS_TRACE_FLAGS_MASK)
  *
  * Protobuf type <code>opentelemetry.proto.logs.v1.LogRecordFlags</code>
  */
 class LogRecordFlags
 {
     /**
-     * Generated from protobuf enum <code>LOG_RECORD_FLAG_UNSPECIFIED = 0;</code>
+     * The zero value for the enum. Should not be used for comparisons.
+     * Instead use bitwise "and" with the appropriate mask as shown above.
+     *
+     * Generated from protobuf enum <code>LOG_RECORD_FLAGS_DO_NOT_USE = 0;</code>
      */
-    const LOG_RECORD_FLAG_UNSPECIFIED = 0;
+    const LOG_RECORD_FLAGS_DO_NOT_USE = 0;
     /**
-     * Generated from protobuf enum <code>LOG_RECORD_FLAG_TRACE_FLAGS_MASK = 255;</code>
+     * Bits 0-7 are used for trace flags.
+     *
+     * Generated from protobuf enum <code>LOG_RECORD_FLAGS_TRACE_FLAGS_MASK = 255;</code>
      */
-    const LOG_RECORD_FLAG_TRACE_FLAGS_MASK = 255;
+    const LOG_RECORD_FLAGS_TRACE_FLAGS_MASK = 255;
 
     private static $valueToName = [
-        self::LOG_RECORD_FLAG_UNSPECIFIED => 'LOG_RECORD_FLAG_UNSPECIFIED',
-        self::LOG_RECORD_FLAG_TRACE_FLAGS_MASK => 'LOG_RECORD_FLAG_TRACE_FLAGS_MASK',
+        self::LOG_RECORD_FLAGS_DO_NOT_USE => 'LOG_RECORD_FLAGS_DO_NOT_USE',
+        self::LOG_RECORD_FLAGS_TRACE_FLAGS_MASK => 'LOG_RECORD_FLAGS_TRACE_FLAGS_MASK',
     ];
 
     public static function name($value)
diff --git a/Opentelemetry/Proto/Metrics/V1/DataPointFlags.php b/Opentelemetry/Proto/Metrics/V1/DataPointFlags.php
index f0f082b..f11029d 100644
--- a/Opentelemetry/Proto/Metrics/V1/DataPointFlags.php
+++ b/Opentelemetry/Proto/Metrics/V1/DataPointFlags.php
@@ -11,28 +11,31 @@
  * bit-field representing 32 distinct boolean flags.  Each flag defined in this
  * enum is a bit-mask.  To test the presence of a single flag in the flags of
  * a data point, for example, use an expression like:
- *   (point.flags & FLAG_NO_RECORDED_VALUE) == FLAG_NO_RECORDED_VALUE
+ *   (point.flags & DATA_POINT_FLAGS_NO_RECORDED_VALUE_MASK) == DATA_POINT_FLAGS_NO_RECORDED_VALUE_MASK
  *
  * Protobuf type <code>opentelemetry.proto.metrics.v1.DataPointFlags</code>
  */
 class DataPointFlags
 {
     /**
-     * Generated from protobuf enum <code>FLAG_NONE = 0;</code>
+     * The zero value for the enum. Should not be used for comparisons.
+     * Instead use bitwise "and" with the appropriate mask as shown above.
+     *
+     * Generated from protobuf enum <code>DATA_POINT_FLAGS_DO_NOT_USE = 0;</code>
      */
-    const FLAG_NONE = 0;
+    const DATA_POINT_FLAGS_DO_NOT_USE = 0;
     /**
      * This DataPoint is valid but has no recorded value.  This value
      * SHOULD be used to reflect explicitly missing data in a series, as
      * for an equivalent to the Prometheus "staleness marker".
      *
-     * Generated from protobuf enum <code>FLAG_NO_RECORDED_VALUE = 1;</code>
+     * Generated from protobuf enum <code>DATA_POINT_FLAGS_NO_RECORDED_VALUE_MASK = 1;</code>
      */
-    const FLAG_NO_RECORDED_VALUE = 1;
+    const DATA_POINT_FLAGS_NO_RECORDED_VALUE_MASK = 1;
 
     private static $valueToName = [
-        self::FLAG_NONE => 'FLAG_NONE',
-        self::FLAG_NO_RECORDED_VALUE => 'FLAG_NO_RECORDED_VALUE',
+        self::DATA_POINT_FLAGS_DO_NOT_USE => 'DATA_POINT_FLAGS_DO_NOT_USE',
+        self::DATA_POINT_FLAGS_NO_RECORDED_VALUE_MASK => 'DATA_POINT_FLAGS_NO_RECORDED_VALUE_MASK',
     ];
 
     public static function name($value)
diff --git a/Opentelemetry/Proto/Metrics/V1/ExponentialHistogramDataPoint.php b/Opentelemetry/Proto/Metrics/V1/ExponentialHistogramDataPoint.php
index 64dde2e..62cb6f5 100644
--- a/Opentelemetry/Proto/Metrics/V1/ExponentialHistogramDataPoint.php
+++ b/Opentelemetry/Proto/Metrics/V1/ExponentialHistogramDataPoint.php
@@ -69,8 +69,8 @@ class ExponentialHistogramDataPoint extends \Google\Protobuf\Internal\Message
      * located at powers of the base, where:
      *   base = (2^(2^-scale))
      * The histogram bucket identified by `index`, a signed integer,
-     * contains values that are greater than or equal to (base^index) and
-     * less than (base^(index+1)).
+     * contains values that are greater than (base^index) and
+     * less than or equal to (base^(index+1)).
      * The positive and negative ranges of the histogram are expressed
      * separately.  Negative values are mapped by their absolute value
      * into the negative range using the same scale as the positive range.
@@ -130,6 +130,17 @@ class ExponentialHistogramDataPoint extends \Google\Protobuf\Internal\Message
      * Generated from protobuf field <code>optional double max = 13;</code>
      */
     protected $max = null;
+    /**
+     * ZeroThreshold may be optionally set to convey the width of the zero
+     * region. Where the zero region is defined as the closed interval
+     * [-ZeroThreshold, ZeroThreshold].
+     * When ZeroThreshold is 0, zero count bucket stores values that cannot be
+     * expressed using the standard exponential formula as well as values that
+     * have been rounded to zero.
+     *
+     * Generated from protobuf field <code>double zero_threshold = 14;</code>
+     */
+    protected $zero_threshold = 0.0;
 
     /**
      * Constructor.
@@ -168,8 +179,8 @@ class ExponentialHistogramDataPoint extends \Google\Protobuf\Internal\Message
      *           located at powers of the base, where:
      *             base = (2^(2^-scale))
      *           The histogram bucket identified by `index`, a signed integer,
-     *           contains values that are greater than or equal to (base^index) and
-     *           less than (base^(index+1)).
+     *           contains values that are greater than (base^index) and
+     *           less than or equal to (base^(index+1)).
      *           The positive and negative ranges of the histogram are expressed
      *           separately.  Negative values are mapped by their absolute value
      *           into the negative range using the same scale as the positive range.
@@ -197,6 +208,13 @@ class ExponentialHistogramDataPoint extends \Google\Protobuf\Internal\Message
      *           min is the minimum value over (start_time, end_time].
      *     @type float $max
      *           max is the maximum value over (start_time, end_time].
+     *     @type float $zero_threshold
+     *           ZeroThreshold may be optionally set to convey the width of the zero
+     *           region. Where the zero region is defined as the closed interval
+     *           [-ZeroThreshold, ZeroThreshold].
+     *           When ZeroThreshold is 0, zero count bucket stores values that cannot be
+     *           expressed using the standard exponential formula as well as values that
+     *           have been rounded to zero.
      * }
      */
     public function __construct($data = NULL) {
@@ -381,8 +399,8 @@ public function setSum($var)
      * located at powers of the base, where:
      *   base = (2^(2^-scale))
      * The histogram bucket identified by `index`, a signed integer,
-     * contains values that are greater than or equal to (base^index) and
-     * less than (base^(index+1)).
+     * contains values that are greater than (base^index) and
+     * less than or equal to (base^(index+1)).
      * The positive and negative ranges of the histogram are expressed
      * separately.  Negative values are mapped by their absolute value
      * into the negative range using the same scale as the positive range.
@@ -402,8 +420,8 @@ public function getScale()
      * located at powers of the base, where:
      *   base = (2^(2^-scale))
      * The histogram bucket identified by `index`, a signed integer,
-     * contains values that are greater than or equal to (base^index) and
-     * less than (base^(index+1)).
+     * contains values that are greater than (base^index) and
+     * less than or equal to (base^(index+1)).
      * The positive and negative ranges of the histogram are expressed
      * separately.  Negative values are mapped by their absolute value
      * into the negative range using the same scale as the positive range.
@@ -660,5 +678,41 @@ public function setMax($var)
         return $this;
     }
 
+    /**
+     * ZeroThreshold may be optionally set to convey the width of the zero
+     * region. Where the zero region is defined as the closed interval
+     * [-ZeroThreshold, ZeroThreshold].
+     * When ZeroThreshold is 0, zero count bucket stores values that cannot be
+     * expressed using the standard exponential formula as well as values that
+     * have been rounded to zero.
+     *
+     * Generated from protobuf field <code>double zero_threshold = 14;</code>
+     * @return float
+     */
+    public function getZeroThreshold()
+    {
+        return $this->zero_threshold;
+    }
+
+    /**
+     * ZeroThreshold may be optionally set to convey the width of the zero
+     * region. Where the zero region is defined as the closed interval
+     * [-ZeroThreshold, ZeroThreshold].
+     * When ZeroThreshold is 0, zero count bucket stores values that cannot be
+     * expressed using the standard exponential formula as well as values that
+     * have been rounded to zero.
+     *
+     * Generated from protobuf field <code>double zero_threshold = 14;</code>
+     * @param float $var
+     * @return $this
+     */
+    public function setZeroThreshold($var)
+    {
+        GPBUtil::checkDouble($var);
+        $this->zero_threshold = $var;
+
+        return $this;
+    }
+
 }
 
diff --git a/Opentelemetry/Proto/Metrics/V1/ExponentialHistogramDataPoint/Buckets.php b/Opentelemetry/Proto/Metrics/V1/ExponentialHistogramDataPoint/Buckets.php
index b9e7f01..e1a90a3 100644
--- a/Opentelemetry/Proto/Metrics/V1/ExponentialHistogramDataPoint/Buckets.php
+++ b/Opentelemetry/Proto/Metrics/V1/ExponentialHistogramDataPoint/Buckets.php
@@ -25,9 +25,9 @@ class Buckets extends \Google\Protobuf\Internal\Message
      */
     protected $offset = 0;
     /**
-     * Count is an array of counts, where count[i] carries the count
-     * of the bucket at index (offset+i).  count[i] is the count of
-     * values greater than or equal to base^(offset+i) and less than
+     * bucket_counts is an array of count values, where bucket_counts[i] carries
+     * the count of the bucket at index (offset+i). bucket_counts[i] is the count
+     * of values greater than base^(offset+i) and less than or equal to
      * base^(offset+i+1).
      * Note: By contrast, the explicit HistogramDataPoint uses
      * fixed64.  This field is expected to have many buckets,
@@ -49,9 +49,9 @@ class Buckets extends \Google\Protobuf\Internal\Message
      *           
      *           Note: This uses a varint encoding as a simple form of compression.
      *     @type int[]|string[]|\Google\Protobuf\Internal\RepeatedField $bucket_counts
-     *           Count is an array of counts, where count[i] carries the count
-     *           of the bucket at index (offset+i).  count[i] is the count of
-     *           values greater than or equal to base^(offset+i) and less than
+     *           bucket_counts is an array of count values, where bucket_counts[i] carries
+     *           the count of the bucket at index (offset+i). bucket_counts[i] is the count
+     *           of values greater than base^(offset+i) and less than or equal to
      *           base^(offset+i+1).
      *           Note: By contrast, the explicit HistogramDataPoint uses
      *           fixed64.  This field is expected to have many buckets,
@@ -95,9 +95,9 @@ public function setOffset($var)
     }
 
     /**
-     * Count is an array of counts, where count[i] carries the count
-     * of the bucket at index (offset+i).  count[i] is the count of
-     * values greater than or equal to base^(offset+i) and less than
+     * bucket_counts is an array of count values, where bucket_counts[i] carries
+     * the count of the bucket at index (offset+i). bucket_counts[i] is the count
+     * of values greater than base^(offset+i) and less than or equal to
      * base^(offset+i+1).
      * Note: By contrast, the explicit HistogramDataPoint uses
      * fixed64.  This field is expected to have many buckets,
@@ -113,9 +113,9 @@ public function getBucketCounts()
     }
 
     /**
-     * Count is an array of counts, where count[i] carries the count
-     * of the bucket at index (offset+i).  count[i] is the count of
-     * values greater than or equal to base^(offset+i) and less than
+     * bucket_counts is an array of count values, where bucket_counts[i] carries
+     * the count of the bucket at index (offset+i). bucket_counts[i] is the count
+     * of values greater than base^(offset+i) and less than or equal to
      * base^(offset+i+1).
      * Note: By contrast, the explicit HistogramDataPoint uses
      * fixed64.  This field is expected to have many buckets,
diff --git a/Opentelemetry/Proto/Trace/V1/Span.php b/Opentelemetry/Proto/Trace/V1/Span.php
index d9da35c..4b1dc13 100644
--- a/Opentelemetry/Proto/Trace/V1/Span.php
+++ b/Opentelemetry/Proto/Trace/V1/Span.php
@@ -18,10 +18,9 @@ class Span extends \Google\Protobuf\Internal\Message
 {
     /**
      * A unique identifier for a trace. All spans from the same trace share
-     * the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes
-     * is considered invalid.
-     * This field is semantically required. Receiver should generate new
-     * random trace_id if empty or invalid trace_id was received.
+     * the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes OR
+     * of length other than 16 bytes is considered invalid (empty string in OTLP/JSON
+     * is zero-length and thus is also invalid).
      * This field is required.
      *
      * Generated from protobuf field <code>bytes trace_id = 1;</code>
@@ -29,10 +28,9 @@ class Span extends \Google\Protobuf\Internal\Message
     protected $trace_id = '';
     /**
      * A unique identifier for a span within a trace, assigned when the span
-     * is created. The ID is an 8-byte array. An ID with all zeroes is considered
-     * invalid.
-     * This field is semantically required. Receiver should generate new
-     * random span_id if empty or invalid span_id was received.
+     * is created. The ID is an 8-byte array. An ID with all zeroes OR of length
+     * other than 8 bytes is considered invalid (empty string in OTLP/JSON
+     * is zero-length and thus is also invalid).
      * This field is required.
      *
      * Generated from protobuf field <code>bytes span_id = 2;</code>
@@ -99,8 +97,8 @@ class Span extends \Google\Protobuf\Internal\Message
      * like server name can be set using the resource API. Examples of attributes:
      *     "/http/user_agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36"
      *     "/http/server_latency": 300
-     *     "abc.com/myattribute": true
-     *     "abc.com/score": 10.239
+     *     "example.com/myattribute": true
+     *     "example.com/score": 10.239
      * The OpenTelemetry API specification further restricts the allowed value types:
      * https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/common/README.md#attribute
      * Attribute keys MUST be unique (it is not allowed to have more than one
@@ -160,17 +158,15 @@ class Span extends \Google\Protobuf\Internal\Message
      *
      *     @type string $trace_id
      *           A unique identifier for a trace. All spans from the same trace share
-     *           the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes
-     *           is considered invalid.
-     *           This field is semantically required. Receiver should generate new
-     *           random trace_id if empty or invalid trace_id was received.
+     *           the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes OR
+     *           of length other than 16 bytes is considered invalid (empty string in OTLP/JSON
+     *           is zero-length and thus is also invalid).
      *           This field is required.
      *     @type string $span_id
      *           A unique identifier for a span within a trace, assigned when the span
-     *           is created. The ID is an 8-byte array. An ID with all zeroes is considered
-     *           invalid.
-     *           This field is semantically required. Receiver should generate new
-     *           random span_id if empty or invalid span_id was received.
+     *           is created. The ID is an 8-byte array. An ID with all zeroes OR of length
+     *           other than 8 bytes is considered invalid (empty string in OTLP/JSON
+     *           is zero-length and thus is also invalid).
      *           This field is required.
      *     @type string $trace_state
      *           trace_state conveys information about request position in multiple distributed tracing graphs.
@@ -209,8 +205,8 @@ class Span extends \Google\Protobuf\Internal\Message
      *           like server name can be set using the resource API. Examples of attributes:
      *               "/http/user_agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36"
      *               "/http/server_latency": 300
-     *               "abc.com/myattribute": true
-     *               "abc.com/score": 10.239
+     *               "example.com/myattribute": true
+     *               "example.com/score": 10.239
      *           The OpenTelemetry API specification further restricts the allowed value types:
      *           https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/common/README.md#attribute
      *           Attribute keys MUST be unique (it is not allowed to have more than one
@@ -242,10 +238,9 @@ public function __construct($data = NULL) {
 
     /**
      * A unique identifier for a trace. All spans from the same trace share
-     * the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes
-     * is considered invalid.
-     * This field is semantically required. Receiver should generate new
-     * random trace_id if empty or invalid trace_id was received.
+     * the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes OR
+     * of length other than 16 bytes is considered invalid (empty string in OTLP/JSON
+     * is zero-length and thus is also invalid).
      * This field is required.
      *
      * Generated from protobuf field <code>bytes trace_id = 1;</code>
@@ -258,10 +253,9 @@ public function getTraceId()
 
     /**
      * A unique identifier for a trace. All spans from the same trace share
-     * the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes
-     * is considered invalid.
-     * This field is semantically required. Receiver should generate new
-     * random trace_id if empty or invalid trace_id was received.
+     * the same `trace_id`. The ID is a 16-byte array. An ID with all zeroes OR
+     * of length other than 16 bytes is considered invalid (empty string in OTLP/JSON
+     * is zero-length and thus is also invalid).
      * This field is required.
      *
      * Generated from protobuf field <code>bytes trace_id = 1;</code>
@@ -278,10 +272,9 @@ public function setTraceId($var)
 
     /**
      * A unique identifier for a span within a trace, assigned when the span
-     * is created. The ID is an 8-byte array. An ID with all zeroes is considered
-     * invalid.
-     * This field is semantically required. Receiver should generate new
-     * random span_id if empty or invalid span_id was received.
+     * is created. The ID is an 8-byte array. An ID with all zeroes OR of length
+     * other than 8 bytes is considered invalid (empty string in OTLP/JSON
+     * is zero-length and thus is also invalid).
      * This field is required.
      *
      * Generated from protobuf field <code>bytes span_id = 2;</code>
@@ -294,10 +287,9 @@ public function getSpanId()
 
     /**
      * A unique identifier for a span within a trace, assigned when the span
-     * is created. The ID is an 8-byte array. An ID with all zeroes is considered
-     * invalid.
-     * This field is semantically required. Receiver should generate new
-     * random span_id if empty or invalid span_id was received.
+     * is created. The ID is an 8-byte array. An ID with all zeroes OR of length
+     * other than 8 bytes is considered invalid (empty string in OTLP/JSON
+     * is zero-length and thus is also invalid).
      * This field is required.
      *
      * Generated from protobuf field <code>bytes span_id = 2;</code>
@@ -513,8 +505,8 @@ public function setEndTimeUnixNano($var)
      * like server name can be set using the resource API. Examples of attributes:
      *     "/http/user_agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36"
      *     "/http/server_latency": 300
-     *     "abc.com/myattribute": true
-     *     "abc.com/score": 10.239
+     *     "example.com/myattribute": true
+     *     "example.com/score": 10.239
      * The OpenTelemetry API specification further restricts the allowed value types:
      * https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/common/README.md#attribute
      * Attribute keys MUST be unique (it is not allowed to have more than one
@@ -533,8 +525,8 @@ public function getAttributes()
      * like server name can be set using the resource API. Examples of attributes:
      *     "/http/user_agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36"
      *     "/http/server_latency": 300
-     *     "abc.com/myattribute": true
-     *     "abc.com/score": 10.239
+     *     "example.com/myattribute": true
+     *     "example.com/score": 10.239
      * The OpenTelemetry API specification further restricts the allowed value types:
      * https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/common/README.md#attribute
      * Attribute keys MUST be unique (it is not allowed to have more than one
diff --git a/Opentelemetry/Proto/Trace/V1/Status/StatusCode.php b/Opentelemetry/Proto/Trace/V1/Status/StatusCode.php
index 0ce2d16..954cf1f 100644
--- a/Opentelemetry/Proto/Trace/V1/Status/StatusCode.php
+++ b/Opentelemetry/Proto/Trace/V1/Status/StatusCode.php
@@ -21,8 +21,8 @@ class StatusCode
      */
     const STATUS_CODE_UNSET = 0;
     /**
-     * The Span has been validated by an Application developers or Operator to have
-     * completed successfully.
+     * The Span has been validated by an Application developer or Operator to 
+     * have completed successfully.
      *
      * Generated from protobuf enum <code>STATUS_CODE_OK = 1;</code>
      */
diff --git a/VERSION b/VERSION
index 96fb87f..1847373 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-v0.19.0
+v0.20.0